土壤是全球陸地生態(tài)系統(tǒng)的主要碳匯之一。土壤碳（C）與土壤氮（N）有著密切相關(guān),土壤氮的動(dòng)態(tài)可以調(diào)節(jié)陸地碳的固存。因此,更好地了解森林土壤C和N平衡,全球和區(qū)域尺度上將天然林（NF）轉(zhuǎn)換為人工林（PF）如何改變土壤C和N周轉(zhuǎn)對(duì)于預(yù)測(cè)和提高陸地生態(tài)系統(tǒng)碳匯具有重要意義。森林土壤儲(chǔ)存了大量的陸地碳,同時(shí)森林不合理的土地利用變化（LUC）能夠?qū)е麓罅緾O₂排放。此外,天然林轉(zhuǎn)變?yōu)槿斯ち帜軌蝻@著影響土壤團(tuán)聚體組成及其C和N庫(kù)儲(chǔ)量響。目前,有關(guān)LUC對(duì)土壤團(tuán)聚體C、N儲(chǔ)量的影響仍存在一定的不確定性,即提高、降低或無(wú)顯著變化。因此,進(jìn)一步開(kāi)展天然林轉(zhuǎn)變?yōu)槿斯ち謱?duì)土壤團(tuán)聚體組成、土壤C和N含量以及不同大小土壤團(tuán)聚體13C和15N豐度影響因素和機(jī)理十分必要。本研究以中國(guó)南北樣帶上相距大約4000公里的6個(gè)地區(qū)（漠河MH、清原QY、信陽(yáng)XY、會(huì)同HT、鼎湖山DH和尖峰嶺JF）的天然林和人工林為研究對(duì)象,測(cè)定了土壤全土和7個(gè)等級(jí)土壤團(tuán)聚體C和N含量,13C and 15N同位素豐度。研究目的:i)天然林轉(zhuǎn)變?yōu)槿斯ち謱?duì)土壤C和N儲(chǔ)量潛力的影響;ii)不同氣候帶條件下,森林轉(zhuǎn)變對(duì)土壤C和N... 

【文章來(lái)源】：福建農(nóng)林大學(xué)福建省

【文章頁(yè)數(shù)】：101 頁(yè)

【學(xué)位級(jí)別】：博士

【文章目錄】：
Appendix List of Abbreviations
摘要
Abstract
Chapter 1 General Introduction
    1.1 Background and problem statement
    1.2 Objectives and hypotheses of the study
        1.2.1 Objectives
        1.2.2 Hypothesis of the study
    1.3 Thesis Structure
Chapter 2 Literature Review
    2.1 Land use change
    2.2. Soil organic carbon stock
        2.2.1 Important controls on C dynamics
        2.2.2 Factors which influence soil organic carbon stock
    2.3 Isotope composition
        2.3.1 Stable isotope
        2.3.2 Natural abundance
    2.4 Soil aggregate
        2.4.1 Soil aggregate stability
        2.4.2 Roles of aggregation factors in the stability of aggregates
        2.4.3 Soil aggregation
Chapter 3 Variability of soil carbon and nitrogen stocks after conversion of natural forestto plantations in Eastern China
    3.1 Introduction
    3.2 Materials and Methods
        3.2.1 Study site and soil sampling
        3.2.2 Statistical analysis
    3.3 Results
        3.3.1 Soil C and N stocks
        3.3.2 Relationship between soil C, N stocks, and underlying factors
    3.4 Discussion
        3.4.1 Effects of land-use change on soil C and N stock
        3.4.2 Effects of soil depth on soil C and N stock
        3.4.3 Effects of bulk density and soil p H on soil C and N stock
        3.4.4 Effects of elevation and stand age on soil C and N stock
        3.4.5 Effects of forest management on soil C and N stock
        3.4.6 Effects of climate factors on soil C and N stock
        3.4.7 Correlation between C and N stock
    3.5 Conclusions
Chapter 4 Effects of Land Use Change from Natural Forest to Plantation on C, N andNatural Abundance of 13C and 15N along a Climate Gradient in Eastern China
    4.1 Introduction
    4.2 Materials and methods
        4.2.1 Study sites and soil sampling
        4.2.2 Soil C and N contents, and δ~(13)C and δ~(15)N analysis
        4.2.3 Statistical analysis
    4.3 Results
        4.3.1 Carbon and nitrogen contents, and C/N ratios in forest floor and mineral soils
        4.3.2 The natural abundance of 13C and 15N in forest floor and mineral soils
        4.3.3 Relationships of climatic factors to C and N contents, C/N ratios and δ~(13)C and δ~(15)N
    4.4 Discussion
        4.4.1 Effects of forest conversion on carbon and nitrogen contents, and C/N ratios in forestfloor and mineral soils
        4.4.2 Effects of forest conversion on natural abundance of 13C and 15N in forest floor andmineral soils
        4.4.3 Effects of climatic factors on carbon, nitrogen and their isotopic abundances
    4.5 Conclusion
Chapter 5 Stable Isotopic Signatures of Carbon and Nitrogen in Soil Aggregates FollowingConversion of Natural Forests to Managed Plantations in Eastern China
    5.1 Introduction
    5.2 Materials and methods
        5.2.1 Study site and sampling
        5.2.2 Soil aggregate fractionation
        5.2.3 Soil C, N concentrations and natural abundance of 13C and 15N analysis
        5.2.4 Statistical analysis
    5.3 Results
        5.3.1 Mass proportion of soil aggregate size fractions
        5.3.2 Soil C and N dynamics in soil aggregates
        5.3.3 Values of δ~(13)C and δ~(15)N in forest floor litter and soil aggregates
        5.3.4 Relationships among soil C and N concentrations, soil δ~(13)C and δ~(15)N, and MAT andMAP
    5.4 Discussion
        5.4.1 Land use change effects
        5.4.2 Variance among site locations
    5.5 Conclusion
Chapter 6 General conclusions and prospects for further research
    6.1 General conclusions
        6.1.1 Variability of soil carbon and nitrogen stocks after conversion of natural forest toplantations in eastern China
        6.1.2 Effects of land use change from natural forest to plantation on C, N and naturalabundance of 13C and 15N along a climate gradient in eastern China
        6.1.3 Stable Isotopic Signatures of Carbon and Nitrogen in Soil Aggregates FollowingConversion of Natural Forests to Managed Plantations in Eastern China
    6.2. Prospects for further research
Acknowledgements
Reference
Published Papers and other Academic Achievements during the Program
    Published papers
    Under review



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